Papers by Keyword: Linearity

Abstract: In recent years, flexible strain sensors with high sensitivity and a wide sensing range have been developed for biosensors, wearable sensors, electronic skin, and soft robots. In this study, SR/CNT/SR composite-based sensors were fabricated using the sandwich manufacturing method. The sensors were then analyzed for electro-mechanical properties to test their performance. The flexible strain sensor showed a high sensitivity of 76.60 at 0-80% strain range. In addition, the sensor also showed a high linearity of 0.978 in one linear region. The sensor also constantly changes relative resistance at 10 cycles in the 0-40% range. While in the 45-80% strain range, the relative resistance value fluctuates. This is due to the large crack in the sensor when stretched. This sensor also has a fast response time of about 80 ms and a fast recovery of around 95 ms. This flexible strain sensor is also stable for durability testing at 500 loading and release cycles.

Abstract: This paper describes two algorithms for generating test signals to efficiently test the linearity of ADCs. Linearity is an important testing item for ADCs, and it takes a long time (hence is costly) to test especially low-sampling-rate, high-resolution ADCs. We have proposed to generate a test signal consisting of multiple-sine waves, to precisely test the linearity for specific important codes (such as around the center of the output codes), using an arbitrary waveform generator (AWG) and an analog filter in our previous studies. Here, we formulate them for general use. Their verification is performed on a single sine wave, and good results are obtained to show the validity of the derivation algorithm.

Abstract: In most schools of engineering, this is among the first interdisciplinary courses that third-year undergraduate students are likely to attend. This presents formidable challenges because any discussion of diffusion phenomena draws heavily on prior knowledge of physics, chemistry, and mathematics. In our traditionally inadequate way of teaching, these disciplines are presented as self-contained, autonomous units. Yet it should be the purpose of any instructor of diffusion theory and practice to show how they may be integrated. Heuristic arguments are certainly appealing — thus recommended — but the methods and tools to be developed must be robust enough to not immediately crumble with use. In that connection, attention to a known and consistent notation is vital. Furthermore, one cannot expect these students to be fully familiar with partial differential equations, and yet, that’s the very nature of the diffusion equation. Its properties must be explained. Finally, diffusion in solids suffers from a bewildering variety of “diffusion coefficients." These must be carefully defined and distinguished. A version of my class-notes will be included in my web-site within a few weeks (just type my name in Google). You are most welcome.

Abstract: Quasi-static absolute calibration is using force with semi-sinusoidal pulse to calibrate pressure measuring system. The pulse width must be wide enough in order to guarantee the effective bandwidth of frequency spectrum be in the flat section of amplitude-frequency characteristics of the tested system. In this way, the result is similar to that from static calibration. The working characteristic parameters for measuring system which is gained from quasi-static calibration is different form static calibration in species, physical meanings and attainment methods. Therefore, the research is of great significance in forming quasi-static calibration system and improving measurement accuracy. The pilot scheme will be introduced in this essay. What is more, the calculation of working characteristic parameters for measuring system will be discussed by taking the force with specific pulse as example, including sensitivity when force transfer to pressure, linearity and repeatability which are used to evaluate the uncertainty of measurement.

Abstract: Product and process conformance are determined by measurements that are taken by a measurement system. A clear understanding of the results of any measurement system requires an understanding of the possible errors within this system. Measurement system errors can be classified into two categories: accuracy and precision. The accuracy of a measurement system is usually broken into three components: bias, linearity and stability and the precision into repeatability and reproducibility. There are a number of procedures which are used, in the automotive and other industries to assess these statistical properties of any measurement system. Usually, companies use repeatability & reproducibility procedures but, according to a measurement systems analysis study, these may not be enough for a company that wants to meet current worldwide quality system standards. Lack of measurement equipment bias and linearity generally is not as predominant error as repeatability and reproducibility, nevertheless, it should be identified because each person that have direct responsibility for measurement evaluation, selection, and control must hand on experience in how to produce a bias and linearity study. A bias study examines the difference between the observed average of the measurements and a reference value. It answers the question “How accurate is my measurement equipment when compared to a master value ”. A linearity study tells one how accurate the measurements are through the expected range of the measurements. It answers the question “Does my measurement equipment have the same accuracy for all sizes of objects being measured ”. Determining the bias and linearity of the measuring equipments and understanding their impact on the measured values will contribute to the effectiveness of the measurement system. In this context, conception and method of bias and linearity analysis of measurement systems are introduced in this paper followed by a real world application done in a major local automotive company. The analysis had ensured consistency of measurements and provided evidence that the measurement system is functioning properly. Minitab software was used to study bias and linearity of the analyzed measurement system.

Abstract: Optimal design of sensitive structure in gas pendulum tilt sensor was discussed. Using ANSYS software, fluid fields produced by heat source of the sensor in center were simulated. According simulated temperature field which is the key sensitive factor of the tilt sensor, optimal design of sensitive structure was discussed further. The results show that sensitivity of sensor is better when the distance between sensor wire and heat source is 0.2 R or 0.3R (R is radius of chamber). In respect to vertical place, experiment and theory show sensor has better sensitivity and linearity when installing angle is 60 ̊ while the horizontal distance between sensor wire and heat source is 0.3R.

Abstract: Electronic current transformers are more suitable for the development of power system compared with traditional electromagnetic current transformers. Rogowski coil current transformer is one of three electric current transformers. According to the measurement principle of Rogowski coils, the equivalent circuit of PCB Rogowski coils is analyzed. By using four PCB Rogowski coils combined, a PCB Rogowski coil current transformer is designed and tested. The results show that the designed PCB Rogowski coil transformer has good linearity and high sensitivity and measurement accuracy and it can meet the requirement of power system.

Abstract: In this article, the necessity of static characteristic test of high temperature pressure sensor was discussed; the principle static characteristic test of high temperature pressure sensor is illustrated; the static testing of high temperature pressure sensor is completed; the static experimental model of high temperature pressure sensor is established; the main technical indexes was established, it provides an important theoretical basis for the application and test of high temperature pressure sensor.

Abstract: The uncertainty contribution related to linearity shall be considered in the calculation of measurement uncertainty when using the impulse voltage measuring system. Under the condition that the national standard is not yet established at present, the paper proposed an experimental method to measure the linearity of 600kV damped capacitive impulse divider (HCR600). The paper used low voltage resistance divider R200S to measure the linearity of generator, and obtained the linearity curve. With the increase of charging voltage, the linearity of divider can be obtained by measuring the charging voltage of impulse voltage generator precisely and its ratio of indicating value of the sample divider HCR600 after corrected. The result shows that the linearity of HCR600 decreases from +0.4% to-0.8%; the maximum difference between positive polarity and negative polarity is 0.14% and the linearity of negative polarity is superior to that of positive polarity. Besides, the paper used a 500kV resistance divider (SMR 7.7/ref500) calibrated by PTB to compare with HCR600, and obtained the linearity curve. By comparison, two curves show a good agreement, the maximum difference between them is 0.15% at the same voltage. The result shows that the method proposed in the paper can be used to measure the linearity of divider accurately. It also can be used as experimental verification in the process of the national standard establishing and to calibrate the ultrahigh voltage impulse voltage measuring equipments when equipments satisfy some requirements.

Abstract: Linearity is a critical parameter to describe positioning errors of touch screens. This paper focuses on a four-wire resistive-type touch screen sensor and tries to find the main factors affecting its linearity. By using the electric field simulation module of ANSYS software, node voltages of conductive layer were analyzed. The mathematical relations between the linearity and individual factors of touch sensor were established and the main factors affecting linearity were identified. Based on optimized sensor parameters, a set of 2.5 inch four-wire resistive touch screen sensors were manufactured and tested with a linearity testing machine. Experimental results show that simulation results and testing results on linearity satisfy the consistency criterion and the analysis results are reliable.